Press Robert H, Hu Lei, Huang Sheng, Hasan Shaakir, Choi J Isabelle, Simone Charles B, Chhabra Arpit M, Gelblum Daphna Y, Kabarriti Rafi, Bakst Richard L, Cracchiolo Jen R, McBride Sean M, Lee Nancy Y
New York Proton Center, New York, NY, USA.
Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
Int J Part Ther. 2023 Feb 16;9(4):253-260. doi: 10.14338/IJPT-22-00032. eCollection 2023 Spring.
After adequate surgical resection, early-stage oral tongue cancer patients can harbor a low risk of local recurrence but remain at risk of regional recurrence. Oral tongue avoidance during adjuvant radiation therapy is an attractive potential treatment strategy to mitigate treatment toxicity. We sought to quantify the dosimetric advantages of this approach and hypothesized that intensity-modulated proton therapy (IMPT) may further reduce organs at risk doses compared with intensity-modulated radiation therapy (IMRT).
Five patients with oral tongue cancer treated with postoperative radiation therapy from August 2020 to September 2021 were retrospectively reviewed. Novel clinical target volume contours, excluding the oral tongue, were generated while maintaining coverage of bilateral at-risk lymph nodes. Comparison IMRT (X) and IMPT (PBT) plans were generated using standard treatment volumes (control) and avoidance volumes (study) (n = 4 plans/patient). Dosimetric variables for organs at risk were compared using the paired test.
The prescribed dose was 60 Gy in 30 fractions. D95% clinical target volume coverage was similar between X and PBT plans for both control and study clinical target volumes. Comparing control with study plans, both X (58.9 Gy vs 38.3 Gy, = .007) and PBT (60.2 Gy vs 26.1 Gy, < .001) decreased the oral cavity dose. The pharyngeal constrictor dose was also reduced ( < .003). There was no difference between control and study plans for larynx ( = .19), parotid ( = .11), or mandible dose ( = .59). For study plans, PBT significantly reduced oral cavity dose (38.3 Gy vs 26.1 Gy, = .007) and parotid dose (23.3 Gy vs 19.3 Gy, = .03) compared with X. For control plans, there was no difference in oral cavity dose using PBT compared with X, but PBT did improve the parotid dose (26.6 Gy vs 19.7 Gy, = .02).
This study quantifies the feasibility and dosimetric advantages of oral tongue avoidance while still treating the at-risk lymph nodes for oral tongue cancer. The dosimetric difference between PBT and X was most prominent with an oral tongue-avoidance strategy.
在进行充分的手术切除后，早期口腔舌癌患者局部复发风险较低，但仍存在区域复发风险。在辅助放疗期间避开口腔舌部是一种有吸引力的潜在治疗策略，可减轻治疗毒性。我们试图量化这种方法的剂量学优势，并假设与调强放射治疗（IMRT）相比，调强质子治疗（IMPT）可能进一步降低危及器官的剂量。
回顾性分析了2020年8月至2021年9月接受术后放疗的5例口腔舌癌患者。在维持双侧危险淋巴结覆盖的同时，生成了不包括口腔舌部的新临床靶区轮廓。使用标准治疗体积（对照）和避开体积（研究）生成对照IMRT（X）和IMPT（PBT）计划（每位患者n = 4个计划）。使用配对检验比较危及器官的剂量学变量。
处方剂量为60 Gy，分30次给予。对于对照和研究临床靶区，X和PBT计划的D95%临床靶区覆盖率相似。将对照计划与研究计划进行比较，X（58.9 Gy对38.3 Gy，P = 0.007）和PBT（60.2 Gy对26.1 Gy，P < 0.001）均降低了口腔剂量。咽缩肌剂量也降低了（P < 0.003）。对照计划与研究计划在喉部（P = 0.19）、腮腺（P = 0.11）或下颌骨剂量（P = 0.59）方面无差异。对于研究计划，与X相比，PBT显著降低了口腔剂量（38.3 Gy对26.1 Gy，P = 0.007）和腮腺剂量（23.3 Gy对19.3 Gy，P = 0.03）。对于对照计划，与X相比，使用PBT时口腔剂量无差异，但PBT确实改善了腮腺剂量（26.6 Gy对19.7 Gy，P = 0.02）。
本研究量化了避开口腔舌部同时仍治疗口腔舌癌危险淋巴结的可行性和剂量学优势。在避开口腔舌部的策略中，PBT和X之间的剂量学差异最为显著。
